The first season had little violence, towards the end of the series we are introduced to Boris, a person who uses other Beybladers as warriors, people who lose with anyone falls down to their death, their training is intensive too as a scene was shown in the Japanese version that some kids were training under a pit of snakes.. Another scene was shown where a kid loses to Tyson, he was dragged away in cell despite him wanting to be freed. Later on in the Japanese version Tyson and the others heard his scream even though they were outside the building.
Season two didn't had any blood but they had deaths of around three people, one of them being Wyaat/Yuuya, he was captured under the influence of being a strong blader if he manages to control the cyber bit-beasts; he wanted to compete with Kai, his influence. Wyaat later on grabbed onto his head as he leans down towards the floor in pain, the team rushes towards him, later on he dies in the Japanese version in front of the Bladebreakers, though in the English dub, it was highly influenced that he was fine and still alive.
Another two deaths take place in a same episode, where falling debris crushes Dr. K and Giddeon, the antagonists whom wanted to capture Tyson and his Bit-Beast. Dr. K was shown to hit a screen of TV whilst he was trying to explode the entire building in a press of a button; he was pushed by Gideon towards the screen, he later on falls to his death and debris collapses on him; after some time, Giddeon gets crushed under debris too.
The last installment of Beyblade, G - Revolution had higher rating, around PG-13 in the Japanese version but due to many dub verions being based on English version, not many people take the violence serious as it's taken out most of the time, or it looks ridiculous with all the music at the background.
In an episode, Kai was shown to have been sliced across his body with sharp nails of a beast, giving him open wounds, blood was shown rushing out of his body in the scene, in the English dub, the clip was cut out. Later on in the same episode, Kai is shown drowning, a huge implement is shown that Kai had died in the episode, he gets sliced again on his chest this time, his arms had scars of blood, along with his face and chest.
In the last episode of G - Revolution, Tyson is shown to get sliced on his chest, giving him three long nailed scars on his chest. The scene was cut out of English dub and the versions based around it.